The 19-year-old man from Deighton suffered severe injuries in the incident on King Street at 1.50am yesterday.

It happened close to the entrance to the Peters department store, halfway down the pedestrianised area.

The victim was taken to Huddersfield Royal Infirmary with what police have described as “a significant head injury.’’

He was later transferred to Leeds General Infirmary for specialist neurological treatment. He was said to be in “poorly but stable’’ today.

The man was standing talking to his girlfriend when he was kicked in the back of the head in a motiveless attack.

The attacker then ran off as people rushed to help the stricken victim.

Detectives are checking CCTV systems to see if the attacker was caught on camera.

Det Sgt Paul Simm from Kirklees CID: “This appears to be a motiveless attack and it is vital that anyone who saw what happens comes forward and talks to us.

“This man has gone for a night out and has ended up badly hurt. We need people with any information to come forward. Even at that time in the morning it will have been busy in the area and people will have seen what happened or the attacker making his getaway.’’

The attacker is said to be an African-Caribbean man in his early 20s.

He wore a blue shirt and black trousers.

Anyone who saw what happened or knows who the attacker is should contact Det Sgt Simm on 0845 6060606 or Crimestoppers on 0800 555 111.